Males will show larger size fairly early. Also males will have pointed saddle, hackle & crest feathers where females will be rounded.
They do in fact have combs-it's a V comb and as in other breeds the male's comb will be larger.

Sorry, it's been years since I last raised any Houdans & I don't recall how long it takes for comb development.
At 7 weeks you should be able to sex with the hackle feathers-look at the feathers close to the head & see if they are pointed or rounded.
Houdans are beautiful birds-you should just keep them

i went out and looked closer to their heads and tucked into their feathers are the buds of teeny little fleshy 'horns'. one is redder than the other so maybe i have one of each!
Thanks for your help.
I would like to keep them but mine free range and the lack of ability to see the bald eagles and such over head isn't good.

From what I've read, the houdans do quite well in free range environment. They are considered a maintenance free breed, just like OEGs. I would check the feathers on their lower back where the tails starts. Rounded=hen pointed= rooster